KENNEDY SPACE CENTER, FLA. - In the Vehicle Assembly Building, Lead Technician Todd Reeves, with United Space Alliance, attaches one of two bolt catchers on orbiter Discovery?s External Tank. A bolt catcher is a vertical bolt mechanism at the forward end of the External Tank that attaches each booster to the tank. At approximately two minutes into launch, SRB separation begins when pyrotechnic devices fire to break the 25-inch, 62-pound steel bolts. One half of the bolt is caught in canister-like "bolt catchers" located on the tank; the other half remains with the boosters. Discovery is flying with a modified bolt catcher, which was upgraded from a two-piece welded design to a one-piece, machine-made design as part of NASA's effort to return to safe, reliable spaceflight. Eliminating the weld makes a structurally stronger bolt catcher design. Though the bolt catcher is mounted on the External Tank, it is considered part of the Solid Rocket Booster element design. It is built by Summa Technologies, Inc. in Huntsville, Ala., insulated at Lockheed Martin?s Michoud Assembly Facility in New Orleans, and installed on the External Tank at KSC.